Dicovery of The Mitsubishi Shindoh

With “Discovery of Mitsubishi Shindoh”, it is possible to respond to various questions such as “what kinds of products Mitsubishi Shindoh manufactures?”, “what kind of people are working?, and what is the purpose of the people?”.
Here, we will introduce the real Mitsubishi Shindoh. First of all, here is a story of the development “MNEX10” which is developed with our own technology.

MNEX10; Cu-Zn based copper which is produced under the future alloy strip (FAST) project for next generation alloy development for which Mitsubishi Shindoh aims in collaboration with Mitsubishi Materials, and is excellent in stress relaxation resistance*.
How could the idea that nobody could come up with be realized? Mr. Kawamura of Mitsubishi Shindoh will ask about this question to three members involved in the aforementioned project.

*Stress relaxation resistance:
Indicator showing excellent spring properties at high temperature, it shows how much the spring weakens after holding for 1,000 hours under the high-temperature environment at 150°C by applying a load (load of 80% with respect to the load strength) in the elastic range that exhibits the spring properties to a certain material.
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Maki Kazunari
  • Teamleader
    Principal Researcher
    Metallurgical Research Department
    Central Research Institute
    Mitsubishi Materials Corporation
  • assignment:overall control
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Iino Ryo
  • Mitsubishi Shindoh Co., Ltd.
    Production Engineering Dept Research & Development Sect.
  • assignment:test production
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Yamashita Daiki
  • Mitsubishi Shindoh Co., Ltd.
    Kitamoto Research Group
    Production Engineering Dept.
  • assignment:research and test
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interviewer: Kawamura Sota
  • Mitsubishi Shindoh Co., Ltd.
    Technology Group Technology Dept.
FAST PROJECT
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Beginning with Customer’s needs

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Kawamura

First, please tell us how you three people are involved in the MNEX10.

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Maki

I was responsible for the development of copper alloys in the project.

At the first time, the development of the MNEX10 was started so as to meet the needs for copper alloys from automobile wire harness manufacturers and terminal manufacturers. Conventionally, Corson alloy (Cu-Ni-Si alloy) is used for a terminal of a vehicle connector; however, we started to develop new copper alloys in order to meet the needs for copper alloys at the low cost with the strength, conductivity, and heat resistance which are similar to colossal alloy.

In order to perfectly satisfy the customer’s need, we have burdened our sales representatives such that they visit our customers many times from the initial stage to specifically confirm the needs. With such an effort, we can make an alloy that is suitable for the customer’s needs.

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Yamashita

I have developed the basic composition of MNEX10 at the laboratory level.

For MNEX10, we have devised how much of the additive elements are added other to zinc so as to achieve performance that meets customer’s needs in order to reduce costs, and can produce performance that meets customer needs.

When I first heard about the concept of the MNEX10 “which has high ecological properties, and is excellent in the balance between properties such as strength, electrical conductivity, and heat resistance at low cost”, I expected that “it will be in great demand”.

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Iino

My role was to make a shape of a product based on the basic compositions that Yamashita et al. had found. Specifically, I engaged in the production of a trial product for the evaluation of the product performance from customers while establishing the manufacturing conditions for production of mass production.

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Overcoming tough time for development

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Kawamura

What kinds of difficulties did you have before MNEX10 could be done?

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Maki

It was difficult to determine the mixing ratio of zinc to other additive elements so as to realize cost down while securing the performance of the colossal alloy such that “the stress relaxation resistance is comparable to that of the colossal alloy, and the strength is in a range of 500 to 650 MPa”. Also, we have to consider manufacturing processes after determining the mixing ratio.

Through the trials and errors for about two years, we were able to get a proper mixing ratio. Thereafter, together with Mr. Iino and Mr. Yamashita, we repeatedly performed the adjustments and optimization for actual production.

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Iino

Even though we had found the mixing ratio, we still continued to struggle. At the laboratory level, even though we find a mixing ratio that gives the desired properties, a problem occurs again when it is applied to the actual manufacturing process.

Since the MNEX10 is the world's first alloy consisting of zinc, tin, nickel, iron, and phosphorus, it was not possible to obtain any reference from Mitsubishi Materials Group and other companies as well. Therefore, it was unexpectedly difficult to prepare the production conditions and to be adapted as a field staff.

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Yamashita

Even though it is clear that the properties are obtained in the experiment, it is not always possible to obtain the same result in the actual manufacturing site.

In order to submit a trial product to the customer within the deadline, the interaction between the manufacturing site and the laboratory should be in hurry.

Sometimes, when we had found some answer, we had worked simultaneously in the laboratory and the manufacturing site so as to save the time for developing in the manufacturing site after obtaining a complete answer in the laboratory.

Personally, since I belonged to a workplace relating to manufacturing so far, it was difficult for me to learn knowledge of alloy development from the beginning.

photoMNEX10 under the evaluation of stress relaxation resistance.The test was repeated such that the fixture became discolored.

photoSample of MNEX10 bent into W shape for evaluation of bending workability. The situation of trials and errors can be found.

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Kawamura

How could you overcome the tough time for development?

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Maki

The research and development of a company is a work that must desperately pursue what can be done under the various constraint conditions such as required performance and cost, and given period and money.

In order to reach the goal by overcoming such a tough time for development, we must strongly hold the desire "to make products useful to the world by any means" with high motivation. I think Mr. Iino and Mr. Yamashita also have the same idea for such manufacturing.

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Iino

You're right. I had the feeling that "the challenge to the world first" and "I wish the products that I made are usefully used by many people", and it was a great motivation for me. I believe that based on the motivation, we were able to achieve mass production through the negotiations and cooperation with the people of the manufacturing site.

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Yamashita

Also in my case, I have kept a high motivation since I was charged for MNEX10.

Because it is the world's first, I knew it was not easy. However, every time I recognized that the results of my works are used for automobile in the world, I felt great rewarding.

photoArticle of MNEX10 of the Japan Metal Society bulletin "Materia"
The MNEX10 was praised for "technological development of innovative new technologies and new products related to the metal industry" and was awarded the Technology Development Award from the Japan Metallurgical Society.

photoPresentation materials for introducing MNEX10
It is clear that it has excellent stress relaxation resistance as compared with existing brass.

Challenge of MNEX10 will be continued.

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Kawamura

What effect did the cooperation of the two companies bring about?

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Maki

Regarding the development of copper alloy products, Mitsubishi Materials mainly focuses on the research, and thus does not have much experience to cope with the problems occurred when the developed alloy is actually manufactured with actual equipment. However, this time, we were able to speedily develop alloys and produce actual equipment together with Mitsubishi Shindoh without wasteful trials & errors.

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Iino

I also strongly felt the synergy effect of the collaboration between two companies. I believe that we were able to maximize our own capabilities by exchanging talented people, and sharing information and facilities, and thus have realized the world first.

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Yamashita

Through the close connection between the research and the manufacturing, there are many things that can be obtained not only as a company but also as individuals. I also learned a lot of things and grew up through interaction with Mr. Maki and Mr. Iino and other members relating to this project, as well.

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Iino

Mitsubishi Shindoh has developed many alloys before the MNEX10 as well. There are also many failures in them. Actually, for me, this project was my first main development, and thus felt heavy responsibility when considering the failed projects, but I think that the success of MNEX10 has rewarded my efforts so far.

photoThree people talking about the thought at the time of development in front of rolled coil of MNEX10

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Kawamura

Please tell us your thoughts on MNEX10 in the future.

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Maki

Currently, the application of the new copper alloy MNEX10 featuring high performance and low price has expanded to areas in addition to the automobile, which was originally targeted for development. In promoting sales activities, we have been inquired about replacing from Corson alloy and phosphor bronze in the consumer field, specifically, terminals for LEDs used for lighting, terminals for industrial equipment, and contact points for breakers.

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Yamashita

Every time when I listen to the fact that MNEX10 is used outside of the automobile field that was supposed during the development, I feel like that my child is growing up, so I am very happy.

Because it is an unconventional copper alloy that has well-balanced properties that in the past, I think that the application will expand still more.

The point of MNEX10 also is to have ecological properties. Firstly, in products, with the excellent stress relaxation resistance, the terminals can be miniaturized, and thus it is possible to reduce the amount of materials used. Furthermore, we do not use rare metals as raw materials, but also add zinc so as to reduce copper consumption by 10%.

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Maki

From the stage of the concept for MNEX10, "do not use materials other than ordinary materials" was emphasized as a constraint condition.

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Iino

On the basis of the concept, the world's first copper alloy was made, it can be said that "we have cooked special dishes from ordinary foodstuffs".

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Yamashita

The ease of procurement of materials is a major advantage when considering global expansion through the production under the licenses.

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Maki

Well, certainly, the MNEX10 has various possibilities.
As the automobile market grows, automobile electronics also have been progressing, and thus the market for automobile terminals has been expanding. It seems to have a big opportunity for the MNEX10 with high performance and low cost.

Having said that, it remains to be seen whether or not the MNEX10 will be widely used in the automobile field and the consumer field in the future. I wish the two companies will continue to cooperate together so as to catch the opportunities in front of us while appealing the attractiveness of the MNEX10 worldwide.

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Kawamura

Thank you very much.

photoWire harness for automobiles is decorated on the background of three people. It is set up in the car for power supply and signal transmission, and many copper alloys are used for the terminal at the tip end, being tightly wrapped in the car for power supply and signal transmission

Introduction of developed alloy

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  • Name:MNEX10
  • Composition:Cu-Zn-Sn-Ni-Fe-P
  • Applications:Automotive, consumer terminal • connector, bus bar, spring for electronic equipment, Contact material such as switch
  • Shape:Products (shaped in a coil shape) and reflow-tin plated products

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